For nearly a century, how behavior develops and is maintained over generations, rather than individually, has been studied through two basic views: creation or upbringing, biology or psychology.
In 1992, two young scientists walking in the footsteps of Freud and Darwin – Moshe Szyf and Michael Meaney – broke into a bar and began creating a revolutionary synthesis of the direct effects of life experiences on genes – not just your own experiences; along with the experiences of your mother, grandmother and older generations. Since the 1970s, scientists have been aware of the need for something extra to tell the DNA stacks within cell nuclei which genes to copy—like for a heart cell or a brain cell.
The methyl group, a common structural component of organic molecules, is one of those extra elements – it binds to DNAs within each cell, selecting only those genes necessary for a particular cell protein. These epigenetic changes were originally believed to occur only during fetal development. However, subsequent research has shown that molecular elements can also be added to DNA during adulthood, causing cellular changes that can result in diseases such as cancer. Methyl groups were attached to DNA, sometimes through a change in diet; sometimes it was due to exposure to certain chemicals. Szyf showed that correcting epigenetic changes through drugs can cure certain types of cancer in animals.
What surprised geneticists was to learn that epigenetic changes can be passed from parent to child, from one generation to the next. Methyl groups could be added and removed without any change in DNA, changes could be inherited as in gene mutations.
Szyf and Meaney hypothesized that if diet and chemicals can cause epigenetic changes, could certain experiences – such as child neglect, substance abuse, or other serious stressors – also cause epigenetic changes in the DNA in human brain neurons? This question led to the emergence of a new field called behavioral epigenetics – a field that has spawned dozens of new research and treatment recommendations to improve the brain.
According to behavioral epigenetics studies, traumatic experiences in our own past or that of our recent ancestors cause molecular scars that permeate our DNA. All these experiences, though forgotten, never go away. They become part of us as molecular residues tightly bound to our genetic makeup. DNA stays the same; however, psychological and behavioral tendencies are inherited. So in addition to your lumpy knees from your grandmother, you may have inherited a predisposition for depression as a result of neglect as a child.
Or you didn’t. If your grandmother was adopted by caring parents, you may also be enjoying what she has earned through their love and support.
Behavioral epigenetic mechanisms are not only based on deficiencies and weaknesses; basically there are strengths and stamina as well. For those unlucky enough to get something from their ailing ancestors, newly developed drug treatments can interfere not only with your mood but also with epigenetic changes. Like your grandmother’s old-fashioned dress; You can wear or change as you wish.